This section is intended to introduce the reader to various aspects of art which may be related to various aspects of the present invention which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
In a TDMA communication system, a base unit facilitates communication between other base units and multiple local mobile terminals (MTs). The base unit and the mobile terminals are typically capable of transmitting and receiving a data signal at a particular frequency or group of frequencies. The data signal is broken into a number of smaller increments known as time slots, which may recur during each cycle of the data signal. During a given communication session, a mobile terminal may be assigned a particular time slot. The data from that mobile terminal may be transmitted in the assigned time slot for the duration of a communication session. For a given base station environment, it is typical for at least some timeslots to be unused at a given time.
FEC is a technology that is useful in improving digital communications, including TDMA communications. In a communication system employing FEC, error correcting parity bits may be transmitted in conjunction with packets containing actual communication data. The error correcting parity bits can be used on the receiving end of a data transmission to reassemble data accurately.
FEC may allow data to be transmitted using lower power than would otherwise be possible because FEC systems are able to overcome or tolerate some degree of erroneous data. The strength of FEC is typically proportional to the number of FEC parity bits that are transmitted for a given number of data bits. Systems employing strong FEC codes (for example, by using more parity bits per data bit) are able to tolerate larger numbers of erroneous data bits and still allow accurate reassembly of data packets. Such systems may facilitate lower transmitter power, longer battery life and increased range of mobile terminals for a given information throughput.
However, the transmission scheme parameters (such as the modulation type, FEC scheme, allowed bandwidth, medium access control and the like) for a given communication system have typically been defined and fixed. In such systems, the only way to increase the range of mobile terminals (or reduce the power consumption for a given range and throughput) has traditionally been to increase the transmitter power, which shortens the battery life. An apparatus and method that improves the FEC capability in TDMA communications systems is desirable.